The present invention relates to a conveyor belt, and more particularly to a conveyor belt for traversing different transport course runs inclusive of straight runs, long and short radius left and right turns, and spiral and helical runs.
In many conveyor belt systems it is required that a long belt transport course be provided in a relatively small space area and for such reason multi-tiered or spiral course conveyors are commonly provided. An example of such use is a bakery operation where baked goods from ovens pass onto spiral conveyors so that a long conveyed travel allows time for goods cooling to take place whereupon goods packaging can follow. To accommodate the conveyor belt following the spiral winding course of a spiral conveyor and for allowing such belt to follow horizontal turn course deviations as well, various constructions of conveyor belts have been developed. These belts will be made of rod and interconnected link elements so that when making a turn, the belt inner edge will undergo a certain condition of foreshortening or collapse, and the belt outer edge will expand or elongate, such collapse or elongation being alteration of belt length at the respective side edges, e.g., from a uniform pitch a belt will have during a straight travel where spacing between successive belt rods will be the same, to lesser or greater pitches at the particular edges.
Because of specifics of these constructions, the radii about which the belt can turn rarely can approach the desirable short turn radius valve of 1.1 times belt width. In other words, the shortest radius most belts can traverse will not be anywhere as low as the desirable value of say, a 22 inch radius turn for a 20 inch wide belt. Many of such constructions are limited in short radius performance by the effect of greatly increased belt tension during turn movement so that attempt to pass the belt into a short radius turn of close to the 1.1 times width dimension can cause belt failure. Further, many belt constructions are suited for turn in one direction only, that is in right or left course deviations. Such single turn direction limitation also precludes turning a belt over to compensate for wear of the upper support face and/or elongation of tractive portions of the belt.
Accordingly, it is desirable to provide an improved belt construction which has bi-directional turn capacity and such as maximizes short radius turn capability.